<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <title>Title</title>
<!--  <script src="lib/jquery-3.5.1.js"></script>-->
      <script src="https://cdn.bootcdn.net/ajax/libs/jquery/3.6.0/jquery.js"></script>
</head>
<body>

<a href="" id="test-jquery">点我</a>

<script>
  // document.getElementById('id');
  // 选择器为CSS选择器
  $('#test-jquery').click(function () {
    alert('hello,jQuery!');
  })
</script>

</body>
</html>